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Title: Geophysical investigation in support of Beaver Dam comprehensive seepage investigation
Authors: United States. Army. Corps of Engineers. Little Rock District.
Llopis, José L.
Butler, Dwain K.
Keywords: Beaver Dam, Arkansas
Geophysical investigation
Publisher: Geotechnical Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Technical report (U.S. Army Engineer Waterways Experiment Station) ; GL-88-6.
Description: Technical Report
Abstract: A comprehensive seepage assessment of Beaver Dam, AR, was performed using a suite of geophysical methods. The Boone Formation, a severely weathered limestone, underlies Dike 1 and has been experiencing seepage since initial filling of the reservoir in 1966. Between the period 1968 and 1971 a grout curtain was constructed at Dike 1 to curtail this seepage. Although the grout curtain reduced the Dike's foundation leakage, recently discovered seeps and boils on the downstream toe of Dike 1 suggest that leakage is increasing to pregrouting levels. Following a recommendation of the May 1984 Dam Safety Assurance Program Reconnaissance Report, a geophysical investigation was undertaken to assess and delineate seepage paths and to map fault zones believed to behave as hydraulic conduits. The geophysical investigation conducted at Dike 1 consisted of self potential (SP), seismic refraction, electrical resistivity, electromagnetic induction, magnetic, downhole water conductivity, and downhole water temperature surveys. Results indicate that the geophysical tests were successful in determining the locations and strike of two faults bounding Dike 1. Results also indicate that seepage is pervasive rather than occurring in a few well defined conduits. Geophysical evidence suggests that the south bounding fault may act as a broad conduit for flow. The seismic refraction surveys indicate that the contact between the weathered limestone (Boone Formation) and the underlying more competent limestone is highly variable in depth. SP results indicate a correlation between SP values and pool elevation. Note: This file is very large. Allow your browser several minutes to download the file.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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